Re: [patch] Real-Time Preemption, -RT-2.6.10-rc2-mm2-V0.7.30-2

From: Rui Nuno Capela
Date: Mon Nov 22 2004 - 12:03:13 EST


> Ingo Molnar
>
> * Rui Nuno Capela <rncbc@xxxxxxxxx> wrote:
>
>> > It seems jackd has a limitation to 14 clients atm (don't ask me why).
>> The
>> > 15th kills jackd ;)
>> >
>>
>> So true.
>
> is there any fix for that? Loading 14 jack_test clients only uses up
> ~33% of CPU time on my testbox. Or should it be possible for me to
> trigger xruns using so many clients and 33% CPU utilization already?
>
> Could you perhaps try 14 instances of jack_test on your box, and see
> whether you can generate similar xruns as you could generate with
> fluidsynth? jack_test should certainly exclude as much jack-client side
> complexity as possible.
>
> Ingo
>

OK. I tried 14 instances of jack_test. I even modded Florian's original
source code, to let each client instance have 4 ins and 4 outs, and to
make things a litle bit heavier, all 4 inputs are mixed into each of the 4
outputs.

Saw at least a couple of XRUNs in a 20 (4*5) minute test-run. CPU load
doesn't get above 30% on my laptop (P4/UP 2.533Ghz).

On attach you may find my "4-multiplex" version of jack_test(.cpp), along
with the jack_test3.sh shell script which has been used for my test runs.

There's also a modified version of nmeter(.c) that served the purpose to
log system performance counters (CPU usage, IRQs and Context Switch
rate).

Bye.
--
rncbc aka Rui Nuno Capela
rncbc@xxxxxxxxx

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